Adults can take Motrin (ibuprofen) every 4 to 6 hours as needed for pain or fever, with a maximum of 1,200 mg in 24 hours when using the over-the-counter strength. Each OTC tablet contains 200 mg, so that works out to no more than six tablets per day. Here’s what you need to know to time your doses safely and get the most relief from each one.
Standard Adult Dosing Schedule
For general pain and fever, the standard OTC dose is 200 to 400 mg (one or two tablets) every 4 to 6 hours. For menstrual cramps, the recommended dose is 400 mg every 4 hours as needed, since cramp pain tends to respond better to slightly more frequent dosing at that higher single dose.
The key number to remember is 1,200 mg per day as the OTC ceiling. That’s three doses of 400 mg or six individual 200 mg tablets spread throughout the day. Prescription-strength ibuprofen can go higher, up to 3,200 mg per day in doses of 400 to 800 mg every 6 to 8 hours, but that range is only appropriate under medical supervision for conditions like rheumatoid arthritis or severe inflammation.
How Long Each Dose Lasts
A single dose of Motrin starts working within 30 to 60 minutes and provides relief for roughly 6 to 8 hours. This is why you don’t always need to redose at the 4-hour mark. If your pain is mild, waiting the full 6 hours between doses keeps your total daily intake lower and reduces the chance of side effects. Reserve the shorter 4-hour interval for days when pain is more intense.
Interestingly, taking Motrin on an empty stomach actually gets the drug into your bloodstream faster and at higher concentrations. A systematic review in the British Journal of Clinical Pharmacology found that eating before a dose delayed absorption significantly, with peak blood levels taking 1.3 to 2.8 times longer to reach compared to taking it on an empty stomach. The peak concentration itself dropped to as low as 44% of what you’d get without food. Higher, earlier blood levels consistently produce better pain relief and longer-lasting effects, meaning you’re less likely to need another dose soon. The common advice to always take ibuprofen with food is based on the idea that it protects your stomach, but the same review found no actual evidence that food prevents gastrointestinal side effects. If your stomach tolerates it fine, taking Motrin without food will get you faster, stronger relief.
Dosing for Children
Children’s Motrin follows a different system entirely. Doses are based on your child’s weight, not their age, and the interval between doses is longer: every 6 to 8 hours rather than every 4 to 6. The typical range is 5 to 10 mg per kilogram of body weight per dose, with a hard ceiling of 40 mg per kilogram per day.
Motrin is not recommended for infants under 6 months old. The FDA has not approved ibuprofen for that age group because safety data is insufficient. For babies and toddlers 6 months and older, liquid Children’s Motrin comes with a dosing syringe and a weight-based chart on the box. Use the weight column, not the age column, if your child is significantly above or below average size.
Adults Over 65
Older adults face higher risks from ibuprofen, particularly kidney problems and fluid retention. A meta-analysis of OTC ibuprofen use in elderly patients with osteoarthritis found that 1,200 mg or less per day for up to 10 days was a viable option, but that framing tells you something important: even researchers treat short-term, low-dose use as the safe boundary for this age group. If you’re over 65 and reaching for Motrin regularly, shorter courses at lower doses are the safest approach.
Who Should Take It Less Often or Not at All
Ibuprofen works by blocking enzymes that produce inflammation, but those same enzymes help maintain blood flow to your kidneys. For most people on an occasional dose, this isn’t a problem. But if your kidneys are already under strain, the effect compounds. People with high blood pressure, heart failure, or chronic kidney disease are at meaningfully higher risk because their kidneys already depend on the exact pathways ibuprofen suppresses. Ibuprofen also causes the body to retain sodium and fluid, which can worsen blood pressure or heart failure symptoms.
Certain medication combinations raise the stakes further. Taking ibuprofen alongside blood pressure drugs (particularly ACE inhibitors or similar medications) or diuretics increases the risk of acute kidney injury. One analysis found the combination raised that risk by 66% compared to either drug alone. If you take blood pressure medication or water pills daily, ibuprofen isn’t necessarily off-limits for a single headache, but using it repeatedly over days or weeks requires a conversation with your prescriber about whether the frequency is safe for you specifically.
Timing Tips for Best Results
Start with the lowest dose that works. If one 200 mg tablet handles your headache, there’s no benefit to taking two. You can always add a second tablet at the next dose if one wasn’t enough. Take Motrin only when you actually have symptoms rather than on a fixed schedule, unless you’re managing something like post-surgical pain where staying ahead of the pain cycle matters.
If you find yourself needing Motrin for more than 10 consecutive days for pain (or more than 3 days for fever), that’s a signal the underlying issue needs a different approach rather than continued OTC dosing. The risks of ibuprofen, particularly to your stomach lining and kidneys, climb with duration of use, not just dose size. Frequency over time matters as much as how many milligrams you take in a single day.